Air exhaust outsole for safety footwear

ABSTRACT

An air exhaust outsole, for safety footwear having an upper with an air permeable insole having a top insole surface for supporting a foot of the wearer, the air exhaust outsole comprising: a midsole, with a top midsole surface engaging a bottom insole surface of the upper, the midsole including at least one ventilation channel between a side midsole surface and the top midsole surface; a puncture resistant layer with a top surface bonded to a bottom midsole surface, the puncture resistant layer comprising a puncture resistant core bonded about at least a peripheral edge in a flexible coating; and a tread layer with: a top surface bonded to a bottom surface of the puncture resistant layer; and a bottom tread surface.

TECHNICAL FIELD

The invention relates to an air exhaust outsole for safety footwear haying a cushioning midsole with air ventilating channels to vent the interior of the upper, and a puncture resistant layer beneath the midsole, to provide a puncture resistant footwear with a ventilated upper.

BACKGROUND OF THE ART

The safe use of footwear in many working environments requires foot protection to avoid common injuries. Protection may include: puncture protection from sharp objects that puncture the sole of the footwear; impact and compression resistance for the toe area; metatarsal protection that reduces the chance of injury to the metatarsal bones at the top of the foot; electrically non-conductive properties which reduce hazards that may result from static electricity buildup, or reduce the possibility of ignition of explosives and volatile chemicals; and reduce the electric hazard risk of stepping on a live electrical wire.

In warehouse operations, manufacturing, heavy industry and construction, workers are required as a minimum to wear protective footwear and head protection, fall protection harnesses and other safety equipment. In general the employer provides, pays for or reimburses the workers for the costs of safety equipment. Footwear being personal and individually sized, is usually purchased by the worker and the costs are reimbursed by the employer. Accordingly workers exercise a high degree of personal choice over the comfort features and fashion when selecting safety footwear.

Safety shoes and boots in particular are widely used throughout workplaces to avoid easily preventable common foot injuries caused by stepping on objects that can puncture the sole of the footwear and injure the sole of the wearer's foot. Governments have established regulations for worker safety and footwear must comply with standard puncture resistance test such as ASTM F241305 (American Society for Testing and Materials) and CSA Z195 (Canadian Standards Association).

Modern protective footwear uses puncture resistant woven fiber layers bonded with rubber or resin. Woven fabric layers use high strength fibers, such as Kevlar™ fibers, spun into thread and tightly woven to replace metal plates that were used in the past to protect the sole of the wearer. Resilient plastic toe caps protect the wearer's toes.

Since footwear used in the workplace is often worn all day everyday, and since employers usually reimburse workers for the cost of safety footwear, comfort is a paramount concern in addition to safety and durability. Many safety footwear designs imitate the appearance and comfort of athletic shoes or dress shoes to enhance comfort as well as to comply with the wearer's fashion choices for their work clothing.

Many common designs for non-safety footwear and running shoes include ventilation of the upper to enhance wearing comfort by circulating air through the upper portion sometimes creating air movement through a pumping action as the wearer walks. Shoes for nurses for example often include superior cushioning, air bags, heel springs and ventilation for comfort due to the physical demands of that profession. Examples of ventilated footwear are described in U.S. Pat. No. 8,127,465 to Byrne et al and U.S. Pat. No. 4,078,321 to Famolare.

When wearing conventional safety footwear that include puncture protective soles, workers often experience discomfort since the protective sole prevents the escape of heat and moisture generated by the wearer's foot and motion. The protective sole may also be made of materials that conduct cold more readily than other conventional materials of the footwear. Metal plates in particular create discomfort since the metal readily conducts cold and heat and therefore modern safety footwear generally uses multiple puncture resistant woven fabric layers that reduce thermal conduction as well as electrical conduction.

Safety footwear are worn outdoors in all weather and are worn all day everyday in many environments, so discomfort from heat, cold, moisture, and water penetration is a serious concern. The protective sole in safety footwear is conventionally located. In the insole adjacent to the wearer's sole. Discomfort arises from the use of a puncture resistant protective layer that is relatively stiff, impedes air circulation, impedes heat dissipation, and impedes moisture transfer that prevents adequate drying of the insole adjacent the wearer's foot.

Accordingly, it is desirable to enhance the comfort of safety footwear while retaining the puncture protection provided by a puncture resistant layer.

Features that distinguish. the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below.

DISCLOSURE OF THE INVENTION

The invention provides an air exhaust outsole, for safety footwear having an upper with an air permeable insole having a top insole surface for supporting a foot of the wearer, the air exhaust outsole comprising: a midsole, with a top midsole surface engaging a bottom insole surface of the upper, the midsole including at least one ventilation channel between a side midsole surface and the top midsole surface; a puncture resistant layer with a top surface bonded to a bottom midsole surface, the puncture resistant layer comprising a puncture resistant core bonded about at least a peripheral edge in a flexible coating; and a tread layer with a top surface bonded to a bottom surface of the puncture resistant layer; and a bottom tread surface.

DESCRIPTION OF THE DRAWINGS

In order that the invention may be readily understood, one embodiment of the invention is illustrated. by way of example in the accompanying drawings.

FIG. 1 is an exploded perspective view of a right foot safety boot where the upper is shown separated from a cushion midsole, a puncture resistant layer and a tread layer.

FIG. 2 is a longitudinal sectional view, along line 2-2 of FIG. 4A, of the air exhaust outsole including four ventilation channels extending transversely through the midsole, with a puncture resistant layer bonded above to the midsole and bonded below to the bottom tread layer.

FIG. 3 is a plan view of the top midsole surface of FIG. 2.

FIGS. 4(A), 4(B), 4(C), 4(D) and 4(F) are external views of a right foot example of the outsole, respectively being: a bottom view; a lateral side view; a medial side view; a front view; and a rear view.

FIG. 5 is a transverse cross-sectional view along line 5-5 of FIG. 4(C).

FIG. 6 is a transverse cross-sectional view along line 6-6 of FIG. 4(C).

FIG. 7 is a transverse cross-sectional view along line 7-7 of FIG. 4(C).

FIG. 8 is a transverse cross-sectional view along line 8-8 of FIG. 4(C).

FIG. 9 is a plan view of the top surface of the puncture resistant layer of FIG. 2.

Further details of the invention and its advantages will be apparent from the detailed description included below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows an air exhaust outsole made of three layered components, namely, the air ventilating midsole 1, the puncture resistant layer 2 and the tread layer 3. The puncture resistant layer 2 is located away from the wearer's foot to enhance comfort since the midsole 1 can provide air ventilation and cushioning between the foot and puncture resistant layer 2 as described in detail below. The safety footwear includes an upper 4 with an air permeable insole 5 having a top insole surface for supporting a foot of the wearer.

As seen in FIGS. 1, 2-3, the midsole 1 has a top midsole surface engaging the bottom insole surface 5 of the upper 4. In the longitudinal sectional view of FIG. 2 and transverse sectional views of FIGS. 6, 7 and 8 it can be seen that the midsole 1 has four transverse ventilation channels 6 that extend between outlet ports 7 in a side midsole surface and inlet ports 8 in the top midsole surface 9.

Therefore each of the four longitudinally spaced apart transverse ventilation channels 6 passes transversely through the midsole 1 and includes an inlet port 8 in the top insole surface 9 and a pair of outlet ports 7 in opposing left and right side midsole surfaces. The inlet 8 and two outlet ports 7 of each channel 6 are in communication via an internal transverse passage formed within the midsole 1.

In the example shown in FIGS. 2 and 3 the inlet port 8 has a central inlet opening 10 to the internal passage. Each inlet opening 10 is joined to at least one adjacent inlet opening 10 with a shallow connecting groove 12 in the top insole surface 9. As seen in FIG. 3, the top insole surface 9 can also include a branching ventilating groove 12 in the ball area of the midsole 1.

The midsole 1 provides a cushion immediately adjacent to the air permeable insole 5 of the upper 4. As a result, the wearer's sole is separated from the puncture resistant layer 2 by a ventilating and cushioning midsole 1 made of a flexible compressible material, for example injection molded ethylene vinyl acetate (IMEVA), commonly known as synthetic foam rubber. The wearer perceives substantially the same foot comfort as a ventilated and cushioned running shoe and does not perceive the discomfort caused by conventional puncture resistant layers that are generally positioned immediately adjacent or relatively close to the insole 5 of the upper 4.

As seen in FIG. 2, and FIGS. 6-8, each ventilation channel 6 has an internal transverse passage joining the inlet port 7 in the top insole surface 9 and the pair of outlet ports 7 in opposing medial and lateral side midsole surfaces. Since the midsole 1 is made of flexible foam material, the top wall 14 of the internal passage can flex toward a bottom wall 15 under the wearer's foot pressure during walking. The top wall 14 rebounds to an initial position when foot pressure is removed, therefore the resilient action of the midsole 1 during walking alternately decreases and restores the air volume within the internal passage to circulate air within the internal passage and ventilate the footwear.

The midsole 1 in the heel area can also include a fluid filled bag (liquid or gas) or a compression spring molded into the foam structure of the midsole 1 in a manner similar to conventional running shoes. The top midsole surface 9 may also include an air/vapour permeable and liquid water resistant membrane such as Gortex™ covering the inlet port 8 to impede entrance of liquid water into the upper 4 from the ventilation channels 6.

FIG. 9 shows a detail plan view of the top surface of the puncture resistant layer 2. The puncture resistant layer 2 is located immediately above the rubber tread layer 3 and is separated from the wearer's sole by the cushioning and ventilating midsole 1. The puncture resistant layer 2 has a top surface bonded to a bottom surface of the midsole 1 and a bottom surface of the puncture resistant layer 2 bonded to the tread layer 3 which has a textured bottom tread surface best seen in FIG. 4(C).

As seen. in FIG. 9, the puncture resistant layer 2 has a. puncture resistant core 16 bonded about at least a peripheral edge in a flexible coating 17. The flexible coating 17 in FIG. 9 is shown as a clear plastic surrounding the periphery of the woven fabric core 16. The toe area of the coating is recessed to allow for the fitting of a protective top cap 18 (shown in FIG. 2). The flexible coating 17 allows the woven fabric puncture resistant core 16 to be bonded to the flexible foam (IMEVA) midsole 1 and also to the rubber (RB) tread layer 3. By encasing the periphery and optionally the bottom of the core 16 in a flexible coating 17, such as thermoplastic urethane (TPU), the mutual bonding of the materials is possible (IMEVA to TPU, TPU to woven fabric, and TPU to RB).

The puncture resistant core 16 can be a puncture resistant woven fabric composite or and a sheet metal plate if desired. A puncture resistant woven fabric core 16 can be assembled from multiple layers of woven fabric bonded together with a resilient layer such as rubber or other adhesive compatible with the threads of the woven fabric. Use of a metal plate as a core 16 in some applications is adequate, however a woven fabric core 16 and/or the flexible coating 17 can be selected to be resistant to electric conduction and thermal conduction. The puncture resistant woven fabric core 16 can be made of threads spun from para-aramid synthetic fiber (Kevlar™) bonded in multiple layers of rubber as for example provided by the Italian manufacturer Lonzi Egisto S.p.a.

The outsole includes a tread layer 3 best seen in FIG. 4(C) that may be molded of rubber (RB) and is bonded to the bottom surface of the puncture resistant layer 2. The flexible coating 17 may cover the bottom surface of the puncture resistant core 16 and can be molded to include ridges or surface features compatible with the mold pattern of the tread layer 3. In the example shown in FIG. 4(C), the flexible coating 17 is transparent and has ridges that match the molded windows 19 in the opaque tread layer 3, through which the transparent flexible coating 17 and puncture resistant core 16 are visible. An advantage of using a transparent flexible coating 17 is that the puncture resistant core 16 with standard markings is visible to confirm that the footwear is puncture resistant.

The outsole described above provides a cushioning and ventilated midsole 1 adjacent the insole 5 and proximal to the wearer's foot sole for enhanced comfort, air circulation, heat dissipation and moisture venting. The location of the puncture resistant layer 2 enables the footwear to provide puncture resistance while avoiding problems that arise if a puncture resistant layer 2 is located close to the wearer's sole, namely, heat retention and moisture retention within the upper 4.

Although the above description relates to a specific preferred embodiment as presently contemplated by the inventors, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein. 

We claim:
 1. An air exhaust outsole, for safety footwear having an upper with an air permeable insole having a top insole surface for supporting a foot of the wearer, the air exhaust outsole comprising: a midsole, with a top midsole surface engaging a bottom insole surface of the upper, the midsole including at least one ventilation channel between a side midsole surface and the top midsole surface; a puncture resistant layer with a top surface bonded to a bottom midsole surface, the puncture resistant layer comprising a puncture resistant core bonded about at least a peripheral edge in a flexible coating; and a tread layer with: a top surface bonded to a bottom surface of the puncture resistant layer; and a bottom tread surface.
 2. The outsole of claim 1 wherein each ventilation channel includes an inlet port in the top insole surface and a pair of outlet ports in opposing left and right side midsole surfaces, the inlet and outlet ports being in communication via an internal passage formed within the midsole.
 3. The outsole of claim 2 wherein the inlet port has a central inlet opening to the internal passage and a coaxial peripheral recess about the inlet opening.
 4. The outsole of claim 2 wherein the midsole includes a plurality of longitudinally spaced apart ventilation channels.
 5. The outsole of claim 4 wherein each inlet inlet port has an inlet opening to the internal, passage, and wherein each inlet opening is joined to at least one adjacent inlet opening with a connecting groove in the top insole surface.
 6. The outsole of claim 5 wherein the top insole surface includes a ventilating groove in a ball area of the insole.
 7. The outsole of claim 1 wherein the midsole comprises a flexible compressible material.
 8. The outsole of claim 7 wherein the flexible compressible material comprises injection molded ethylene vinyl acetate (IMEVA).
 9. The outsole of claim 7 wherein the ventilation channel has an internal passage between an inlet port in the top insole surface and a pair of outlet ports in opposing left and right side midsole surfaces, wherein the internal passage has a top wall that flexes toward a bottom wall thereof under foot pressure and returns to an initial position when foot pressure is removed, thereby alternately decreasing and restoring an air volume within the internal passage to pump air within the internal passage.
 10. The outsole of claim 1 wherein the midsole in a heel area includes one of: a fluid filled bag; and a compression spring.
 11. The outsole of claim 2 wherein the top midsole surface includes an air permeable water resistant membrane covering the inlet port.
 12. The outsole of claim 1 wherein the puncture resistant core comprises one of: a puncture resistant woven fabric composite; and a sheet metal plate.
 13. The outsole of claim 12 wherein the puncture resistant woven fabric composite comprises multiple layers of woven fabric bonded together with a resilient, layer therebetween, and wherein the resilient layer comprises rubber.
 14. The outsole of claim 1 wherein at least one of: the puncture resistant core; and the flexible coating, are resistant to at least one of: electric conduction; and thermal conduction.
 15. The outsole of claim 1 wherein the flexible coating covers the bottom surface of the puncture resistant layer.
 16. The outsole of claim 1 wherein the flexible coating comprises thermoplastic urethane (TPU).
 17. The outsole of claim 16 wherein the flexible coating is transparent.
 18. The outsole of claim 12 wherein the puncture resistant woven fabric comprises threads spun from para-aramid synthetic fiber (Kevlar™).
 19. The outsole of claim 1 wherein the tread layer comprises rubber (RB).
 20. The outsole of claim 16 wherein tread layer is opaque and includes windows through which the flexible coating and puncture resistant core are visible. 